Home Forums Hunting & Shooting Rimfires Bergara BMR Trigger Mod

Saw this over on RimfireCentral thought I'd pass it along. Obviously do at your own risk. It's not difficult but if you are not confident have a gunsmith do it for you.

You can easily adjust the sear on your Bergara BMR Trigger by tapping the existing hole shown in pic with 4-40 tap and installing a 1/2" 4-40 set screw. Works great - my trigger could easily be set to 1#. I ended up setting it at 2# and now have an excellent trigger.

Borrowed pics, hope OP does not get mad....


FWIW: Stock Trigger screw on bottom of trigger doesn't do much. Mine was about to fall out when I took the stock off. It only adds tension to the trigger spring when turned in. In pic you can see what is going on. Arrow points to hole to be threaded and where set screw will push on trigger to shorten sear engagement. Top hole in trigger assembly shows trigger engagement so you can actually see how much you are adjusting engagement.

Thanks. I just got one and will have to try doing the modification.

tag

I have a 4-40 tap, tap handle and 1 extra 4-40x1/2" set screw I bought just for this project. I'd send along to the next guy for $25 if you need the stuff to do it.

The hole in the trigger housing is a little oversized for 4-40, at least the screws I had were very loose in the tapped hole. The screw I installed would move slightly with each trigger pull, changing the pull weight. Get it where you want and use some type of thread locker before snapping again to preserve the gain.

tagged for reference

Good point, did the same with blue Lock-tite.

All good things to know guys, thanks.

Mark

Instead of using a #4-40 screw which is .112 diameter, could you use a #5-40 which is .125 diameter? This might take care of the loose fitting #4 screw. For reference, tap drill size for a #4 -40 is .089" (or a #43 drill) diameter and the tap drill size for a #5-40 is .1015 (or a #38 drill)

That is certainly an option, but sourcing a #5-40 tap, a #38 drill bit and #5-40 set screws is going to require ordering from a specialty supply house. There’s nothing available in #5 around here.

McMaster Carr has everything you need
https://www.mcmaster.com/91375A181/ set screws
https://www.mcmaster.com/26035a277/ taper tap
https://www.mcmaster.com/8947a192/ drill bit

Amazon has a drill bit and tap combo as well
https://www.amazon.com/Drill-America-POU5-40-5-40-Length/dp/B06ZZ5C37X/ref=sr_1_2?crid=3B7EM4DXILPMQ&keywords=%2338+drill+bit&qid=1649256000&sprefix=+38+drill+bit%2Caps%2C161&sr=8-2

and set screws (they are shorter than 1/2" but should work
https://www.amazon.com/5-40-16-Socket-Screws-Point/dp/B07HP6X6PV/ref=sr_1_2?crid=LOX2E98EHYCF&keywords=5-40+set+screw&qid=1649256083&sprefix=5-40+se%2Caps%2C191&sr=8-2

Pullit, thanks for the links. It saves me the time to look those items up.
I was referring to walking into a local industrial supply store. I prefer to do it that way if possible.
Unfortunately, Covid has forced the closure of a couple of these supply houses that were rather close to me. With the price of fuel nowadays it’s probably a cheaper option to order them online.

Most of the supply houses around my neck of the woods will tell you the same thing "we don't have it, but we can order it". Seems very few places stock much of anything any more except what is common as dirt. One hardware store near me does do a decent job of stocking number size drill bits.

4-40 works just fine with a dot of blue lock tite on the set screw.

Following
Hank